Fluid replacement device

ABSTRACT

A fluid replacement method including: determining the amount of urine expelled by a patient; infusing via a pump fluid from a first fluid source into a patient; determining an amount of fluid infused into the patient from the first fluid source; adjusting the operating of the pump based on the determined amount of urine expelled and the amount of fluid infused into the patient; setting a desired fluid balance for the patient; setting an amount of at least one additional fluid delivered to the patient, wherein the at least one additional fluid is not pumped into the patient; calculating an actual fluid balance based on the determined urine output, the determined amount of fluid infused into the patient from the first fluid source, and the set amount of said at least one additional fluid delivered to the patient; and automatically controlling the pump based on the actual fluid balance and the set desired fluid balance so the actual fluid balance conforms to the desired fluid balance.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/657,144, now U.S. Pat. No. 10,045,734, filed Jan. 14, 2010, andclaims the benefit of and priority to U.S. Provisional Application Ser.No. 61/206,254, filed on Jan. 28, 2009.

FIELD OF THE INVENTION

The subject invention relates to fluid management systems.

BACKGROUND OF THE INVENTION

Systems have been proposed to automatically measure the fluid deliveredto a patient and fluids expelled or taken from a patient.

U.S. Pat. No. 4,291,692, for example, discloses and IV drop counter, aurine drop counter, and a microcomputer controlling an infusion pump.U.S. Pat. No. 7,029,456 discloses a “networked” system with no less thanfour separate units. See also U.S. Pat. No. 4,994,026 disclosingseparate load scales and a control unit primarily used for dialysis.

In a cath lab, for example, a patient has a contrast agent injected intohis veins, the patient's vessels are imaged, and a therapy isadministered, e.g., a stent or the like is inserted into the patient.After this procedure, the contrast agent will collect in the patient'skidneys. The toxic nature of these contrast agents are well documentedas is contrast nephropathy. See corresponding application Ser. No.10/936,945 published as Published Patent Application No. 2006/0052764incorporated herein by this reference.

Also, during cardiac surgery, the patient may be administered a fairamount of fluid. After surgery, a diuretic may be administered and thenurse instructed to allow the patient to expel urine at a rate greaterthan fluid administered to the patient (e.g., drugs, nutritionalsupplements, saline, sodium bicarbonate, and the like). Managing thisprescribed fluid balance can be difficult and time consuming.

BRIEF SUMMARY OF THE INVENTION

Accordingly, it is desirable to hydrate the patient sufficiently toencourage the patient to urinate and expel the toxic contrast agent andalso to infuse the patient with fluid to balance the urine expelled bythe patient with the fluid infused into the patient so that the patientdoes not become dehydrated.

But, the cath lab and other surgical and recovery sites are too smalland crowded to accommodate separate urine drop counters, weight scales,or “networked” units. Moreover, the attending nurses do not have thetime to learn complex systems. This is perhaps why the proposed systemsof the prior art have not been commercially successful.

It is therefore an object of the invention to provide a new automatedfluid replacement device. In one preferred embodiment, the new fluidreplacement device is self-contained. The device also automaticallytakes into account fluid taken by the patient from multiple sources. Thedevice has a user friendly interface where the nurse can enter differentsettings and a display which provides the information the nurse needs.Once the desired settings are entered, the device operatesautomatically.

It is a further object of the invention, in one example, to provide adevice which can automatically provide therapy, even when, for example,a patient's urine output is less than the amount of fluid infused intothe patient.

A fluid replacement device in accordance with an example of theinvention includes a console with a weighing subsystem responsive to afirst fluid source and a urine collection chamber, and a pump configuredto pump fluid from the first fluid source into a patient. A processingsubsystem in the console is responsive to the weighing subsystem and isconfigured to determine, based on the weight of the first fluid sourceand the weight of the urine collection chamber, the patient's urineoutput and the amount of fluid infused into the patient from the firstfluid source. The processing subsystem is further configured to controlthe pump to adjust the operation of the pump based on the patient'surine output and the amount of fluid infused into the patient. A userinterface in the console allows the user to set a desired fluid balancefor the patient and to set an amount of at least one additional fluiddelivered to the patient. The processing subsystem is responsive tothese settings and is further configured to automatically calculate thepatient's actual fluid balance based on the determined urine output, thedetermined amount of fluid infused into the patient from the first fluidsource, and the set amount of the at least one additional fluiddelivered to the patient. The pump is controlled based on the actualfluid balance and the set desired fluid balance until the actual fluidbalance is the same as or approximately the same as the desired fluidbalance.

The typical user interface includes a display and the processingsubsystem may be configured to display the actual fluid balance, the setdesired fluid balance, the determined urine output, the determinedamount of fluid infused into the patient, and the set amount of the atleast one additional fluid delivered to the patient.

The processing subsystem may further be configured to automaticallydetect when the determined urine output is less than a set fluidbalance. In response, the processing subsystem controls the pump toinfuse a minimum preset amount of fluid from the source of fluid. Theprocessing subsystem can also automatically detect when the determinedurine output is greater than the total of the determined amount of fluidinfused into the patient and the set amount of the at least oneadditional fluid delivered to the patient and, in response, it controlsthe pump to infuse fluid from the first source of fluid until the actualfluid balance equals or approximates the set desired fluid balance.

In one version, there are means for setting an amount of at least oneadditional fluid expelled by the patient. The processing subsystem isresponsive to this setting and is configured to calculate an actualfluid balance based on the determined urine output, the determinedamount of fluid infused into the patient from the first fluid source,the set amount of the at least on additional fluid delivered to thepatient, and the set amount of the at least one additional fluidexpelled by the patient.

There may also be means for setting a bolus amount of fluid to beinjected into the patient from the first fluid source. Then, theprocessing subsystem is further configured to be responsive to the setbolus amount and to control the pump until the actual fluid balance isthe same as or approximately the same as the set bolus amount.

One novel fluid replacement device comprises a console including a pumpinfusing fluid from a first fluid source into a patient, and aprocessing subsystem configured to determine the patient's urine outputand the amount of fluid infused into the patient from the first fluidsource. The processing subsystem is also configured to control the pumpto adjust the operation of the pump based on the patient's urine outputand the amount of fluid infused into the patient. A user interface inthe console allows the user to set a desired fluid balance for thepatient and set an amount of at least one additional fluid delivered tothe patient. The processing subsystem is responsive to these setting andautomatically calculates the actual fluid balance based on thedetermined urine output, the determined amount of fluid infused into thepatient from the first fluid source, and the set amount of the at leastone additional fluid delivered to the patient. The pump is controlledbased on the actual fluid balance and the set desired fluid balanceuntil the actual fluid balance is the same as or approximately the sameas the desired fluid balance.

The subject invention also features a fluid replacement method. Theamount of urine expelled by a patient is determined. Fluid from a firstfluid source is infused into a patient. The amount of fluid infused intothe patient from the first fluid source is determined. The operation ofthe pump is adjusted based on the patient's urine output and the amountof fluid infused into the patient.

A desired fluid balance for the patient can be set. An amount of atleast one additional fluid delivered to the patient can be input. Anactual fluid balance is calculated based on the determined urine output,the determined amount of fluid infused into the patient from the firstfluid source, and the set amount of the at least one additional fluiddelivered to the patient. The pump is controlled based on the actualfluid balance and the set desired fluid balance until the actual fluidbalance is the same as or approximately the same as the desired fluidbalance.

Urine expelled by the patient may be collected in a urine collection bagand determining the amount of urine expelled by the patient mayincluding weighing the collection bag. Also, determining the amount thefluid infused into the patient from the first fluid source may includeweighing the first fluid source. The actual fluid balance, the setdesired fluid balance, the determined urine output, the determinedamount of fluid infused into the patient, and the set amount of at leastone additional fluid delivered to the patient are all quantities whichare typically displayed.

The method may further include detecting when the determined urineoutput is less than a set fluid balance and, in response, controllingthe pump to automatically infuse a minimum preset amount of fluid fromthe source of fluid. The method may further include detecting when thedetermined urine output is greater than the total of the determinedamount of fluid infused into the patient and the set amount of the atleast one additional fluid delivered to the patient and, in response,controlling the pump to automatically infuse fluid from the source offluid until the actual fluid balance equals or approximates the setdesired fluid balance.

The method may further include setting an amount of at least oneadditional fluid expelled by the patient and calculating an actual fluidbalance based on the determined urine output, the determined amount offluid infused into the patient from the first fluid source, the setamount of the at least one additional fluid delivered to the patient,and the set amount of the at least one additional fluid expelled by thepatient.

The method may further include setting a bolus amount of fluid to beinfused into the patient from the fluid source and automaticallycontrolling the pump until the actual fluid balance is the same as orapproximately the same as the set bolus amount.

The subject invention, however, in other embodiments, need not achieveall these objectives and the claims hereof should not be limited tostructures or methods capable of achieving these objectives.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Other objects, features and advantages will occur to those skilled inthe art from the following description of a preferred embodiment and theaccompanying drawings, in which:

FIG. 1 is a block diagram depicting the primary components associatedwith an example of a fluid management system in accordance with thesubject invention;

FIG. 2 is a schematic front view of a fluid management deviceincorporating the components depicted in FIG. 1 in an integrated manner;

FIG. 3 is a schematic view of the display of the device shown in FIG. 2;

FIG. 4 is a view of the display shown in FIG. 3 configured to allow theuser to set a desired fluid balance;

FIG. 5 is a view of the display shown in FIG. 3 configured to allow theuser to set the amount of another fluid delivered to the patient;

FIG. 6 is a schematic view of the display shown in FIG. 3 allowing theuser to set the amount of fluid expelled by the patient other thanurine;

FIG. 7 is a flow chart depicting the primary steps associated with theprogramming of the processing subsystem shown in FIG. 1 and alsodepicting the primary steps associated with a fluid balancing method inaccordance with the subject invention;

FIG. 8 is a graph showing a therapy scenario where the desired fluidbalance setting is positive;

FIG. 9 is a graph showing a therapy scenario where the desired fluidbalance setting is negative;

FIG. 10 is a graph showing a therapy scenario where fluid intake fromanother source has been set by the user;

FIG. 11 is a schematic view of the display shown in FIG. 3 configured toallow the user to set a bolus setting; and

FIG. 12 is a graph showing the results of a patient therapy where abolus setting has been entered by the user.

DETAILED DESCRIPTION OF THE INVENTION

Aside from the preferred embodiment or embodiments disclosed below, thisinvention is capable of other embodiments and of being practiced orbeing carried out in various ways. Thus, it is to be understood that theinvention is not limited in its application to the details ofconstruction and the arrangements of components set forth in thefollowing description or illustrated in the drawings. If only oneembodiment is described herein, the claims hereof are not to be limitedto that embodiment. Moreover, the claims hereof are not to be readrestrictively unless there is clear and convincing evidence manifestinga certain exclusion, restriction, or disclaimer.

Fluid replacement system 10, FIG. 1, in one example, includes weighingsubsystem 12 responsive to both the weight of urine collection chamber14 and source of fluid 16.

Pump 18 is configured to pump fluid from source 16 into a patient asshown. Pump 18 is controlled by processing subsystem 20, e.g., acomputer, a field programmable gate array, application specificintegrated circuit, microprocessor, controller, or the like.

Processing subsystem 20 is configured to be responsive to weighingsubsystem 12 and is configured (e.g., programmed) to determine, based onthe weight of fluid source 16, the amount of fluid infused into thepatient over some interval (e.g., an hour). Processing subsystem 20 mayalso monitor the operation history of pump 18 to determine the amount offluid infused into the patient from source 16. Other means fordetermining the amount of fluid infused into the patient are within thescope of the subject invention. Processing subsystem 20 furtherdetermines, based on the weight of urine collection chamber 14, thepatient's urine output over some interval. Other means for determiningurine output are possible. The programming associated with processingsubsystem 20 then typically controls pump 18 to adjust the operation ofpump 18 based on the patient's urine output and the amount of fluidinfused into the patient (e.g., manually or from other infusion pumps,IV drops, and the like).

There are also means for setting a desired fluid balance for a givenpatient and for setting an amount of at least one additional fluiddelivered to the patient. Such means may include user interface 22(e.g., a monitor and keyboard or touch screen). As shown, the setdesired balance may be stored in memory 24 associated with processingsubsystem 20 and a set amount of the at least one additional fluiddelivered to the patient (“other intake”) may also be stored in memory24. Memory 24 can also be used to store default values for variousparameters.

Processing subsystem 20 includes programming which takes theseparameters as inputs and calculates an actual patient fluid balancebased on the determined urine output, the determined amount of fluidinfused into the patient from the first fluid source, and the set amountof the at least one additional fluid delivered to the patient by othermeans. Processing subsystem 20 controls pump 18 based on the actualfluid balance and the set desired fluid balance until the actual fluidbalance is the same as or approximately the same as the desired fluidbalance.

FIG. 2 depicts one preferred fluid management device includingintegrated console 30 including weighing subsystem 12, FIG. 1, pump 18,processing subsystem 20, memory 24, and user interface 22 in the form ofmenu driven touch screen display 32. Chain 34 is connected on one end tothe weighing subsystem inside console 30 (e.g., one or more straingauges) and includes a hook for hanging fluid source 16 (e.g., a salinebag). Chain 36 is also connected on one end to the weighing subsysteminside console 30 and terminates in a hook for hanging urine bag 14.Tubing 38 extends from fluid source 16 through pump 18 and to a needleinserted into the vein of a patient. Tubing 40 extends from a catheterconnected to the patient's urinary tract to urine collection bag 14. SeePublished Patent Application No. 2006/0052764 incorporated herein bythis reference.

The result is a stand alone integrated device which can be coupled to Npole 42 and moved with the patient when he leaves the cath lab asopposed to multiple units wired together or “networked” units.

FIG. 3 shows how the processing subsystem is configured to display, ondisplay 32, FIG. 2, the determined infused amount at 50, FIG. 3, thedetermined urine output at 52, the set “other” patient fluid intake at54, the calculated actual fluid balance at 56, and the desired fluidbalance at 58. All amounts are typically in milliliters. The presenturine output rate is calculated and displayed as shown in 60. Touchscreen menu area 62 allows the user to input and set a desired fluidbalance, the “other intake,” and, in one embodiment, other fluidsexpelled by the patient, if known. Once set, these parameters aredisplayed as shown. In FIG. 4, the desired fluid balance can be setusing buttons 70 a and 70 b. In FIG. 5, the other fluid intake can beset using buttons 72 a and 72 b. In FIG. 6, the other fluid output canbe set using buttons 74 a and 74 b. All three menus are activated byselecting the “settings” area 62, FIG. 3.

Processing subsystem 20, FIG. 1 is programmed as shown in FIG. 7. Apatient may have a contrast agent injected to his veins, and the patientwill have been imaged and subject to some form of a therapy such as theintroduction of a stent. Or, the patient may be recovering from surgeryand administered saline, drugs, nutritional supplements, and the like.Once the patient's urinary tract is connected to urine collection bag14, FIG. 2 and the saline bag is connected to the patient, therapybegins at some point during the patient's stay in the cath lab or otherlocation. At step 100, the patient's urine output is determined. The set“other intake” is read (see display area 62, FIG. 3) from memory 24,FIG. 1, step 102, FIG. 7. The fluid infused amount is determined, step104, based on the weight of source 16, FIG. 2. The desired fluid balanceis read from memory 24, FIG. 1 (see display area 62, FIG. 3), step 106,FIG. 7. If there has been a setting for fluid expelled by the patientother than collected in urine collection chamber 14, FIG. 2, thatquantity is also read, step 108, FIG. 7.

Then, processing subsystem 20, FIG. 1, determines the actual fluidbalance, step 110, FIG. 7 and displays it (see display area 56, FIG. 3).The actual fluid balance is the amount infused via pump 18, FIG. 1 plusthe set “other intake” less the urine output collected in chamber 14,FIG. 1 and any set “other output.”

In step 112, FIG. 7, the calculated actual fluid balance is compared tothe set desired balance (see display area 58, FIG. 3). If the balance isperfect or within a predetermined range, no action is taken as shown atstep 112 in FIG. 7. If the calculated fluid balance is less than or morethan the desired set fluid balance by a predetermined amount, however,processing subsystem 20, FIG. 1 controls pump 18, step 114, FIGS. 7 toinject less or more fluid from fluid source 16, FIG. 1 until the actualfluid balance equals or approximates the desired fluid balance.

FIG. 8 shows how at the beginning of therapy, a desired fluid balance of+100 ml/hr is set, the actual urine output is determined to be 100 ml inthe first hour as shown at 120. In response, processing subsystem 20,FIG. 1 controls pump 18 to infuse the patient with 200 ml of fluid fromsource 16 as shown at 122 in FIG. 8. This particular scenario assumesthe “other intake” is set at 0. FIG. 8 also shows the determined urineoutput is compared to the infused amount during the second throughfourth hours of therapy.

FIG. 9 shows an example of where the desired fluid balance is negative.FIG. 10 shows a scenario where the “other intake” has been set by thenurse (see 54, FIG. 3). In the first hour, this patient has expelledonly about 25 ml but has taken in about 100 ml of fluid from the “otherintake” source. The desired balance is set to zero. In this case,processing subsystem 20, FIG. 1 detects that the desired urine output isless than a set fluid balance and is programmed, in response, to controlpump 18, FIG. 1 to infuse a minimum preset amount of fluid from thesource of fluid as shown at 126 in FIG. 10. This minimum preset amountof fluid may be 10 ml per hour, for example, a sufficient amount to keepthe patient's vein open, but the default amount may be changed by theuser via display 32, FIG. 2.

In the second hour, the patient's urine output is 200 ml but the amountinfused is only about 25 ml and again, the set fluid received by thepatient from another source is about 100 ml. Processing subsystem 20,FIG. 1, detects that the urine output is greater than the total of thedetermined amount of fluid infused into the patient and the set amountof the additional fluid delivered to the patient and, in response, theprocessing subsystem is programmed to control pump 18, FIG. 1 to infusefluid from the source of fluid until the actual fluid balance equals orapproximates the set desired fluid balance as shown in hours three andfour of the therapy depicted in FIG. 10.

FIG. 11 shows how, via touch screen area 62 of touch screen display 32,the user can select infusion settings as shown at 130 which brings upbolus setting 132 which can be adjusted up or down via arrows 134 a and134 b. A bolus may be prescribed by a physician and the inventionuniquely allows the nurse to insert a prescribed bolus setting whichprocessing subsystem 20, FIG. 1 automatically delivers by controllingpump 18. In FIG. 12, the bolus has been set by the nurse to 250 ml andin the first 30 minutes of therapy, as shown at 150, the full bolusamount has been delivered to the patient by processing subsystem 20,FIG. 1 controlling pump 18 to deliver a bolus of fluid from fluid source16. After determining that the patient's urine output was about 25 ml asshown at 152 in FIG. 12, processing subsystem 20, FIG. 1 controls pump18 to deliver from fluid source 16, 275 mL of fluid as shown at 154.Thereafter, balancing proceeds as shown in FIG. 12. The result is ahighly versatile, integrated, easy to use automated system for use inthe cath lab or other hospital site to prevent nephropathy, dehydration,over-hydration, and the like.

Although specific features of the invention are shown in some drawingsand not in others, this is for convenience only as each feature may becombined with any or all of the other features in accordance with theinvention. The words “including”, “comprising”, “having”, and “with” asused herein are to be interpreted broadly and comprehensively and arenot limited to any physical interconnection. Moreover, any embodimentsdisclosed in the subject application are not to be taken as the onlypossible embodiments.

In addition, any amendment presented during the prosecution of thepatent application for this patent is not a disclaimer of any claimelement presented in the application as filed: those skilled in the artcannot reasonably be expected to draft a claim that would literallyencompass all possible equivalents, many equivalents will beunforeseeable at the time of the amendment and are beyond a fairinterpretation of what is to be surrendered (if anything), the rationaleunderlying the amendment may bear no more than a tangential relation tomany equivalents, and/or there are many other reasons the applicant cannot be expected to describe certain insubstantial substitutes for anyclaim element amended.

Other embodiments will occur to those skilled in the art and are withinthe following claims.

The invention claimed is:
 1. A fluid replacement method comprising:determining an amount of urine excreted by a patient; infusing via apump fluid from a first fluid source into the patient; determining anamount of the fluid infused into the patient from the first fluidsource; setting a desired fluid balance for the patient; setting anamount of at least one additional fluid delivered to the patient,wherein the at least one additional fluid is not pumped into thepatient; calculating an actual fluid balance based on the determinedamount of urine excreted, the determined amount of the fluid infusedinto the patient from the first fluid source, and the set amount of theat least one additional fluid delivered to the patient; and adjustingoperation of the pump to adjust the fluid infused into the patient basedon the actual fluid balance and the set desired fluid balance so theactual fluid balance conforms to the desired fluid balance.
 2. Themethod of claim 1 in which urine excreted by the patient is collected ina urine collection bag and the determination of the amount of urineexcreted by the patient includes weighing the urine collection bag. 3.The method of claim 1 in which the determination of the amount of thefluid infused into the patient from the first fluid source includesweighing the first fluid source.
 4. The method of claim 1 furtherincluding displaying the actual fluid balance, the set desired fluidbalance, the determined amount of urine excreted, the determined amountof the fluid infused into the patient, and the set amount of the atleast one additional fluid delivered to the patient.
 5. The method ofclaim 1 wherein, when the determined amount of urine excreted is lessthan the set desired fluid balance, the adjusting of the operation ofthe pump comprises infusing into the patient a minimum preset amount ofthe fluid from the first fluid source.
 6. The method of claim 1 wherein,when the determined amount of urine excreted is greater than a total ofthe determined amount of the fluid infused into the patient and the setamount of the at least one additional fluid delivered to the patient,the adjusting of the operation of the pump comprises infusing fluid fromthe first fluid source until the actual fluid balance equals orapproximates the set desired fluid balance.
 7. The method of claim 1further including setting an amount of at least one additional fluidexcreted by the patient, wherein the at least one additional fluidexcreted is not urine.
 8. The method of claim 7 wherein the calculatingthe actual fluid balance is additionally based on the set amount of theat least one additional fluid excreted by the patient.
 9. The method ofclaim 1 further including setting a bolus amount of fluid to be infusedinto the patient from the first fluid source.
 10. The method of claim 9further including automatically controlling the pump until the actualfluid balance is at or within a predetermined range of the set bolusamount.